Method and apparatus for retransmitting uplink data configured in discontinuous reception in a wireless communication system

ABSTRACT

The disclosure relates to a communication technique for converging a 5G communication system, which is provided to support a higher data transmission rate beyond a 4G system with an IoT technology, and a system therefor. The disclosure may be applied to intelligent services (e.g., smart home, smart building, smart city, smart car or connected car, health care, digital education, retail business, security and safety related service, or the like) based on the 5G communication technology and the IoT related technology. The embodiment of the disclosure relates to an uplink data retransmission method. In addition, the embodiment of the disclosure relates to a method for adjusting time synchronization of an uplink.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 U.S.C. §119(a) of a Korean patent application number 10-2018-0021658, filed onFeb. 23, 2019, in the Korean Intellectual Property Office, thedisclosure of each of which is incorporated by reference herein in itsentirety.

BACKGROUND 1. Field

Various embodiments of the disclosure relate to a method for performingan uplink transmission (grant) configured in a wireless communicationsystem and a discontinuous reception (DRX) operation for reducing powerconsumption of a terminal.

In addition, the disclosure relates to a method for adjusting timesynchronization of an uplink.

2. Description of Related Art

To meet a demand for radio data traffic that is on an increasing trendsince commercialization of a 4G communication system, efforts to developan improved 5G communication system or a pre-5G communication systemhave been conducted. For this reason, the 5G communication system or thepre-5G communication system is called a beyond 4G network communicationsystem or a post LTE system. To achieve a high data transmission rate,the 5G communication system is considered to be implemented in a veryhigh frequency (mmWave) band (e.g., like 60 GHz band).

To relieve a path loss of a radio wave and increase a transfer distanceof the radio wave in the very high frequency band, in the 5Gcommunication system, beamforming, massive MIMO, full dimensional MIMO(FD-MIMO), array antenna, analog beam-forming, and large scale antennatechnologies have been discussed. Further, to improve a network of thesystem, in the 5G communication system, technologies such as an evolvedsmall cell, an advanced small cell, a cloud radio access network (cloudRAN), an ultra-dense network, a device to device communication (D2D), awireless backhaul, a moving network, cooperative communication,coordinated multi-points (CoMP), and reception interference cancellationhave been developed. In addition to this, in the 5G system, hybrid FSKand QAM modulation (FQAM) and sliding window superposition coding (SWSC)that are an advanced coding modulation (ACM) scheme and a filter bankmulti carrier (FBMC), a non-orthogonal multiple access (NOMA), and asparse code multiple access (SCMA) that are an advanced accesstechnology, and so on have been developed.

Meanwhile, the Internet is evolved from a human-centered connectionnetwork through which a human being generates and consumes informationto the Internet of Things (IoT) network that transmits/receivesinformation between distributed components such as things and processesthe information. The Internet of Everything (IoE) technology in whichthe big data processing technology, etc., is combined with the IoTtechnology by connection with a cloud server, etc. has also emerged. Toimplement the IoT, technology elements, such as a sensing technology,wired and wireless communication and network infrastructure, a serviceinterface technology, and a security technology, have been required.Recently, technologies such as a sensor network, machine to machine(M2M), and machine type communication (MTC) for connecting betweenthings has been researched.

In the IoT environment, an intelligent Internet technology (IT) servicethat creates a new value in human life by collecting and analyzing datagenerated in the connected things may be provided. The IoT may beapplied to fields, such as a smart home, a smart building, a smart city,a smart car or a connected car, a smart grid, health care, smartappliances, and an advanced healthcare service, by fusing and combiningthe existing information technology (IT) with various industries.

Therefore, various tries to apply the 5G communication system to the IoTnetwork have been conducted. For example, technologies such as thesensor network, the machine to machine (M2M), and the machine typecommunication (MTC), have been implemented by techniques such as thebeamforming, the multiple input multiple output (MIMO), and the arrayantenna that are the 5G communication technologies. The application ofthe cloud radio access network (cloud RAN) as the big data processingtechnology described above may also be considered as an example of thefusing of the 5G communication technology with the IoT technology.

SUMMARY

The disclosure is directed to provision of a method for enabling aterminal to retransmit configured uplink at the time of simultaneouslyoperating an uplink transmission (grant) configured in a wirelesscommunication system and a discontinuous reception (DRX) operation forreducing power consumption of the terminal.

Further, the disclosure is directed to provision of a method forconfiguring a switching operation of a bandwidth part of an additionaluplink and uplink synchronization when a bandwidth part of one downlinkand a bandwidth part of two uplinks are activated simultaneously, incase of considering an additional uplink newly introduced in a nextgeneration mobile communication system.

Objects of the disclosure are not limited to the above-mentionedobjects. That is, other objects that are not mentioned may be obviouslyunderstood by those skilled in the art to which the disclosure pertainsfrom the following description.

According to the embodiment of the disclosure, the terminal can monitorthe signal from the base station only when the retransmission isrequired for the configured uplink, and can perform the uplinkretransmission.

In addition, according to the embodiment of the disclosure, it ispossible to clarify the ambiguity of the switching operation of thebandwidth parts which may occur according to the partial frequency bandnewly introduced in the next generation mobile communication system andthe additional uplink, that is, how to perform the switching operationof the bandwidth part in the case of the additional uplink, and embodythe operation of the terminal by clarifying the method for configuringuplink synchronization according to the configuration of the additionaluplink.

In accordance with an aspect of the disclosure, a method by a terminalin a wireless communication system is provided. The method includesreceiving, from a base station, a system information block includinginformation associated with a transmission timing for an uplink signalto be transmitted on a supplementary uplink (SUL) bandwidth part (BWP),determining the transmission timing for the uplink signal based on theinformation, and transmitting, to the base station, the uplink signal onthe SUL BWP based on the determined transmission timing.

In accordance with an aspect of the disclosure, a method by a basestation in a wireless communication system is provided. The methodincludes transmitting, to a terminal, a system information blockincluding information associated with a transmission timing for anuplink signal to be transmitted on a supplementary uplink (SUL)bandwidth part (BWP), and receiving, from the terminal, the uplinksignal on the SUL BWP based on the transmission timing, wherein thetransmission timing for the uplink signal is determined by the terminalbased on the information.

In accordance with an aspect of the disclosure, a terminal in a wirelesscommunication system is provided. The terminal includes a transceiverconfigured to transmit and receive signals, and a controller configuredto receive, via the transceiver from a base station, a systeminformation block including information associated with a transmissiontiming for an uplink signal to be transmitted on a supplementary uplink(SUL) bandwidth part (BWP), determine the transmission timing for theuplink signal based on the information, and transmit, via thetransceiver to the base station, the uplink signal on the SUL BWP basedon the determined transmission timing.

In accordance with an aspect of the disclosure, a base station in awireless communication system is provided. The base station includes atransceiver configured to transmit and receive signals, and a controllerconfigured to transmit, via the transceiver to a terminal, a systeminformation block including information associated with a transmissiontiming for an uplink signal to be transmitted on a supplementary uplink(SUL) bandwidth part (BWP), and receive, via the transceiver from theterminal, the uplink signal on the SUL BWP based on the transmissiontiming, wherein the transmission timing for the uplink signal isdetermined by the terminal based on the information.

In accordance with an aspect of the disclosure, a method by a terminalin a wireless communication system is provided. The method includesreceiving, from a base station, a message for configuring adiscontinuous reception (DRX) operation, receiving, from the basestation, data based on a semi-persistent scheduling (SPS) configuration,transmitting, to the base station, feedback information corresponding tothe data and starting a hybrid automatic repeat and request (HARQ) roundtrip time (RTT) timer for a HARQ process corresponding to the data,after the end of a transmission of the feedback information.

In accordance with an aspect of the disclosure, a method by a terminalin a wireless communication system is provided. The method includesreceiving, from a base station, a message for configuring adiscontinuous reception (DRX) operation, transmitting, to the basestation, a configured uplink grant based on a configured grantconfiguration and starting a hybrid automatic repeat and request (HARQ)round trip time (RTT) timer for a HARQ process corresponding to theconfigured uplink grant, after a first repetition of a transmissionaccording to the configured grant configuration.

In accordance with an aspect of the disclosure, a method by a basestation in a wireless communication system is provided. The methodincludes transmitting, to a terminal, a message for configuring adiscontinuous reception (DRX) operation, transmitting, to the terminal,data based on a semi-persistent scheduling (SPS) configuration andreceiving, from the terminal, feedback information corresponding to thedata, wherein a hybrid automatic repeat and request (HARQ) round triptime (RTT) timer for a HARQ process corresponding to the data is startedby the terminal, after the end of a transmission of the feedbackinformation.

In accordance with an aspect of the disclosure, a method by a basestation in a wireless communication system is provided. The methodincludes transmitting, to a terminal, a message for configuring adiscontinuous reception (DRX) operation and receiving, from theterminal, a configured uplink grant based on a configured grantconfiguration, wherein a hybrid automatic repeat and request (HARQ)round trip time (RTT) timer for a HARQ process corresponding to theconfigured uplink grant is started by the terminal, after a firstrepetition of a transmission according to the configured grantconfiguration.

In accordance with an aspect of the disclosure, a terminal in a wirelesscommunication system is provided. The terminal includes a transceiverconfigured to transmit and receive signals and a controller configuredto receive, via the transceiver from a base station, a message forconfiguring a discontinuous reception (DRX) operation, receive, via thetransceiver from the base station, data based on a semi-persistentscheduling (SPS) configuration, transmit, via the transceiver to thebase station, feedback information corresponding to the data, and starta hybrid automatic repeat and request (HARQ) round trip time (RTT) timerfor a HARQ process corresponding to the data, after the end of atransmission of the feedback information.

In accordance with an aspect of the disclosure, a terminal in a wirelesscommunication system is provided. The terminal includes a transceiverconfigured to transmit and receive signals and a controller configuredto receive, via the transceiver from a base station, a message forconfiguring a discontinuous reception (DRX) operation, transmit, via thetransceiver to the base station, a configured uplink grant based on aconfigured grant configuration, and start a hybrid automatic repeat andrequest (HARQ) round trip time (RTT) timer for a HARQ processcorresponding to the configured uplink grant, after a first repetitionof a transmission according to the configured grant configuration.

In accordance with an aspect of the disclosure, a base station in awireless communication system is provided. The base station includes atransceiver configured to transmit and receive signals and a controllerconfigured to transmit, via the transceiver to a terminal, a message forconfiguring a discontinuous reception (DRX) operation, transmit, via thetransceiver to the terminal, data based on a semi-persistent scheduling(SPS) configuration, and receive, via the transceiver from the terminal,feedback information corresponding to the data, wherein a hybridautomatic repeat and request (HARQ) round trip time (RTT) timer for aHARQ process corresponding to the data is started by the terminal, afterthe end of a transmission of the feedback information.

In accordance with an aspect of the disclosure, a base station in awireless communication system is provided. The base station includes atransceiver configured to transmit and receive signals and a controllerconfigured to transmit, via the transceiver to a terminal, a message forconfiguring a discontinuous reception (DRX) operation, and receive, viathe transceiver from the terminal, a configured uplink grant based on aconfigured grant configuration, wherein a hybrid automatic repeat andrequest (HARQ) round trip time (RTT) timer for a HARQ processcorresponding to the configured uplink grant is started by the terminal,after a first repetition of a transmission according to the configuredgrant configuration.

The effects that may be achieved by the embodiments of the disclosureare not limited to the above-mentioned objects. That is, other effectsthat are not mentioned may be obviously understood by those skilled inthe art to which the disclosure pertains from the following description.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document: the terms “include” and “comprise,” aswell as derivatives thereof, mean inclusion without limitation; the term“or,” is inclusive, meaning and/or; the phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean toinclude, be included within, interconnect with, contain, be containedwithin, connect to or with, couple to or with, be communicable with,cooperate with, interleave, juxtapose, be proximate to, be bound to orwith, have, have a property of, or the like; and the term “controller”means any device, system or part thereof that controls at least oneoperation, such a device may be implemented in hardware, firmware orsoftware, or some combination of at least two of the same. It should benoted that the functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for certain words and phrases are provided throughout thispatent document, those of ordinary skill in the art should understandthat in many, if not most instances, such definitions apply to prior, aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1A illustrates a structure of an LTE system according to anembodiment of the disclosure.

FIG. 1B illustrates a radio protocol structure in the LTE systemaccording to an embodiment of the disclosure.

FIG. 1C illustrates a timing for performing a discontinuous receptionoperation to reduce power consumption of a terminal according to anembodiment of the disclosure.

FIG. 1D illustrates a frame structure in which the terminal schematizesa data transmission in a configured uplink transmission according to anembodiment of the disclosure.

FIG. 1E illustrates an operation sequence of the terminal when DRX and aconfigured downlink/uplink transmission according to an embodiment ofthe disclosure are simultaneously set.

FIG. 1F illustrates a configuration of the terminal according to anembodiment of the disclosure.

FIG. 2A illustrates a structure of an LTE system according to anotherembodiment of the disclosure.

FIG. 2B illustrates a radio protocol structure in the LTE systemaccording to another embodiment of the disclosure.

FIG. 2C illustrates a structure of a next generation mobilecommunication system according to another embodiment of the disclosure.

FIG. 2D illustrates a radio protocol structure of a next generationmobile communication system according to an embodiment of thedisclosure.

FIG. 2E illustrates a scenario in which a bandwidth part is applied inthe next generation mobile communication system according to anembodiment of the disclosure.

FIG. 2F illustrates a diagram for applying an additional uplinkfrequency according to an embodiment of the disclosure.

FIG. 2G illustrates a bandwidth part switching operation in a generalserving cell according to an embodiment of the disclosure.

FIG. 2H illustrates a bandwidth part switching operation in a servingcell in which an additional uplink according to an embodiment of thedisclosure is configured.

FIG. 2I illustrates a BWP switching operation in a case where twouplinks exist in an operation of a terminal according to an embodimentof the disclosure.

FIG. 2J illustrates a BWP timer expiration operation in a case where twouplinks exist in an operation of a terminal according to an embodimentof the disclosure.

FIG. 2K illustrates an operation of the terminal according to anembodiment of the disclosure, in particular, a method for setting, by aterminal, uplink time synchronization in a serving cell where anadditional uplink is configured.

FIG. 2L illustrates a configuration of the terminal according to anembodiment of the disclosure.

FIG. 2M illustrates a configuration of a base station according to anembodiment of the disclosure.

DETAILED DESCRIPTION

FIGS. 1A through 2M, discussed below, and the various embodiments usedto describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

Hereinafter, an operation principle of the disclosure will be describedin detail with reference to the accompanying drawings. Hereinafter, whenit is determined that the detailed description of the known art relatedto the disclosure may obscure the gist of the disclosure, the detaileddescription thereof will be omitted. Further, the followingterminologies are defined in consideration of the functions in thedisclosure and may be construed in different ways by the intention orpractice of users and operators. Therefore, the definitions thereofshould be construed based on the contents throughout the specification.

Terms identifying an access node, terms indicating network entity, termsindicating messages, terms indicating an interface between networkentities, terms indicating various types of identification information,and so on that are used in the following description are exemplified forconvenience of explanation. Accordingly, the disclosure is not limitedto terms to be described below and other terms indicating objects havingthe equivalent technical meaning may be used.

Hereafter, for convenience of explanation, the disclosure uses terms andnames defined in the 3rd generation partnership project long termevolution (3GPP LTE) that is the latest standard among the currentlycommunication standards. However, the disclosure is not limited to theterms and names but may also be identically applied even to the systemaccording to other standards. In particular, the disclosure may beapplied to 3GPP new radio (NR: 5G mobile communication standard).

First Embodiment

FIG. 1A illustrates a structure of an LTE system according to anembodiment of the disclosure.

Referring to FIG. 1A, the wireless communication system is configured toinclude a plurality of base stations 1 a-05, 1 a-10, 1 a-15, and 1 a-20,a mobility management entity (MME) 1 a-25, and a serving-gateway (S-GW)1 a-30. A user equipment (hereinafter, UE or terminal) 1 a-35 accessesan external network via the base stations 1 a-05, 1 a-10, 1 a-15, and 1a-20 and the S-GW 1 a-30.

The base stations 1 a-05, 1 a-10, 1 a-15, and 1 a-20 are access nodes ofa cellular network and provide a radio access to terminals that accessesa network. That is, in order to serve traffic of users, the basestations 1 a-05, 1 a-10, 1 a-15, and 1 a-20 collect and schedule statusinformation such as a buffer status, an available transmission powerstatus, a channel status of the terminals, thereby supporting aconnection between the terminals and a core network (CN). The MME 1 a-25is an apparatus for performing various control functions as well as amobility management functions for the terminal and is connected to aplurality of base stations, and the S-GW 1 a-30 is an apparatus forproviding a data bearer. Further, the MME 1 a-25 and the S-GW 1 a-30 mayfurther perform authentication, bearer management, and the like on theterminal accessing the network and may process packets that are to bereceived from the base stations 1 a-05, 1 a-10, 1 a-15, and 1 a-20 andpackets that are to be transmitted to the base stations 1 a-05, 1 a-10,1 a-15, and 1 a-20.

FIG. 1B illustrates a radio protocol structure in the LTE systemaccording to an embodiment of the disclosure. The NR to be defined belowmay be partially different from the radio protocol structure in thefigure, but will be described for convenience of explanation of thedisclosure.

Referring to FIG. 1B, the radio protocol of the LTE system includespacket data convergence protocols (PDCPs) 1 b-05 and 1 b-40, radio linkcontrols (RLCs) 1 b-10 and 1 b-35, and medium access controls (MACs) 1b-15 and 1 b-30 in the terminal and the ENB, respectively.

The packet data convergence protocols (PDCPs) 1 b-05 and 1 b-40 performsoperations such as compression/recovery of an IP header, and the radiolink controls (hereinafter, referred to as RLC) 1 b-10 and 1 b-35reconfigure a PDCP packet data unit (PDU) to be an appropriate size. TheMACs 1 b-15 and 1 b-30 are connected to several RLC layer devicesconfigured in one terminal and perform an operation of multiplexing RLCPDUs in an MAC PDU and demultiplexing the RLC PDUs from the MAC PDU.Physical layers 1 b-20 and 1 b-25 perform an operation of channel-codingand modulating upper layer data, making the upper layer data as an OFDMsymbol and transmitting them to a radio channel, or demodulating andchannel-decoding the OFDM symbol received through the radio channel andtransmitting the demodulated and channel-decoded OFDM symbol to theupper layer.

Further, the physical layer uses an HARQ (Hybrid ARQ) for additionalerror correction and a receiving end transmits whether to receive thepacket transmitted from a transmitting end as 1 bit. This is called HARQACK/NACK information. The downlink HARQ ACK/NACK information on theuplink transmission may be transmitted on a physical hybrid-ARQindicator channel (PHICH) physical channel, and the uplink HARQ ACK/NACKinformation on the downlink transmission may be transmitted on aphysical uplink control channel (PUCCH) or physical uplink sharedchannel (PUSCH) physical channel. The PUCCH is used to transmit not onlyfor HARQ ACK/NACK information, but also downlink channel statusinformation (CSI), a scheduling request (SR), and the like to the basestation by the terminal. The SR is 1-bit information, and if theterminal transmits an SR to a resource in the PUCCH configured by thebase station, the base station recognizes that the correspondingterminal has data to be transmitted to the uplink, and allocates anuplink resource. The terminal can transmit a detailed buffer statusreport (BSR) message as the uplink resource. The base station mayallocate a plurality of SR resources to one terminal.

Meanwhile, the PHY layer may consist of one or a plurality offrequency/carriers, and a technology of simultaneously setting and usinga plurality of frequencies in one base station is called carrieraggregation (hereinafter, referred to as CA) technology. Unlike usingonly one carrier for communication between the terminal (or userequipment (UE)) and the base station (E-UTRAN NodeB, eNB), the CAtechnology additionally uses a main carrier and one or a plurality ofsub-carriers to be able to surprisingly increase throughput as many asthe number of sub-carriers. Meanwhile, in the LTE, a cell within thebase station using the main carrier is called a primary cell (PCell) andthe sub-carrier is called a secondary cell (SCell).

The technology for extending the CA function to two base stations isreferred to as dual connectivity (hereinafter, referred to as DC)technology. In the DC technology, the terminal simultaneously connectsand uses a master base station (Master E-UTRAN Node B, hereinafterreferred to as MeNB) and a secondary base station (Secondary E-UTRANNode B, hereinafter referred to as SeNB), and cells belonging to themaster base station are referred to as a master cell group (hereinafter,referred to as MCG) and cells belonging to the secondary base stationare called a secondary cell group (hereinafter, referred to as SCG).There are representative cells for each cell group. The representativecell for the master cell group is referred to as a primary cell(hereinafter, referred to as PCell), and the representative cell for thesecondary cell group is referred to as a primary secondary cell(hereinafter, referred to as PSCell). When the above-mentioned NR isused, the MCG uses the LTE technology, and the SCG uses the NR, suchthat the terminal may simultaneously use the LTE and the NR.

Although not illustrated in the drawings, each radio resource control(hereinafter, referred to as RRC) layer is present at an upper part ofthe PDCP layer of the terminal and the base station, and the RRC layermay receive and transmit access and measurement related configurationcontrol messages for a radio resource control. For example, the terminalmay be instructed to perform the measurement using the RRC layermessage, and the terminal may report the measurement result to the basestation using the RRC layer message.

Meanwhile, the transmission units of the PCell and the SCell may be thesame or different. For example, in the LTE, the transmission units ofPCell and SCell may be the same in 1 ms unit, but in the NR, thetransmission unit (slot) in the PCell is 1 ms, but the transmission unitin the SCell can be 0.5 ms in length.

The following table shows information on the length of the slotavailable in each serving cell (that is, PCell or SCell) according tonumerology (or subcarrier spacing) used by each serving cell in the NR.

TABLE 1 information on the length of the slot Subcarrier spacing (kHz)15 30 60 120 240 Length (ms) of 1 0.5 0.25 0.125 0.00625 transmissionunit (slot) The number of 1 2 4 8 12 slots in subframe (1 ms)

In addition, in the LTE and NR, the following units are used in a framestructure in a radio interval (i.e. between the base station and theterminal).

-   -   Radio frame: It has a length of 10 ms and is identified by a        system frame number (SFN) for each radio frame.    -   Subframe: It has a length of 1 ms, in which the radio frame has        10 subframes. The subframe is identified by subframe numbers 0        to 9 within each radio frame.    -   Slot: It has a length according to a value set as shown in the        table, and is a transmission unit used when the base station and        the terminal transmit data.

FIG. 1C illustrates a discontinuous reception (hereinafter, referred toas DRX) operation of a terminal according to an embodiment of thedisclosure.

The DRX is a technology of monitoring only some PDCCHs according to theabove configuration information, instead of monitoring all physicaldownlink control channels (hereinafter, PDCCH below) to obtainscheduling information according to the configuration of the basestation, thereby minimizing power consumption of the terminal.Accordingly, the terminal monitors the PDCCH only at the time calledActive Time. The above Active Time means the time below: whendrx-onDurationTimer or drx-InactiveTimer, drx-RetransmissionTimerDL,drx-RetransmissionTimerUL, or ra-ContentionResolutionTimer is activated;or when the above timer is still pended according to transmitting ascheduling request to the base station; or when a random access response(RAR) for a random access preamble that the terminal does not selectdirectly is received and then PDCCH allocated to the C-RNTI of theterminal was not received from the base station.

The basic DRX operation has a DRX cycle 1 c-00 and monitors the PDCCHonly for an on-duration 1 c-05 time. In the connection mode, the DRXcycle has two values of long DRX and short DRX. In general, the long DRXcycle is applied, and, if necessary, the base station can set theadditional short DRX cycle. If both the long DRX cycle and the short DRXcycle are set, the terminal starts the short DRX timer and at the sametime, repeats from the short DRX cycle, and if there is no new trafficuntil the short DRX timer expires, the terminal is changed from theshort DRX cycle to the long DRX cycle.

If the scheduling information for a new packet is received by the PDCCHfor the on-duration 1 c-05 time (1 c-10), the terminal starts a DRXinactivity timer 1 c-15. The terminal maintains an active state duringthe DRX inactivity timer. That is, the PDCCH monitoring is continued.

In addition, the terminal also starts a HARQ RTT timer 1 c-20. The HARQRTT timer is applied to prevent the terminal from unnecessarilymonitoring the PDCCH during HARQ round trip time (HARQ RTT), and theterminal does not need to perform the PDCCH monitoring during the timeroperation time. However, while the DRX inactivity timer and the HARQ RTTtimer are operated simultaneously, the terminal continues to monitor thePDCCH based on the DRX inactivity timer.

If the HARQ RTT timer expires, the DRX retransmission timer 1 c-25starts. While the DRX retransmission timer is operated, the terminalneeds to perform the PDCCH monitoring for transmission/reception of theretransmission of the previous data. Generally, during the DRXretransmission timer operation, the scheduling information for HARQretransmission is received (1 c-30). Upon receiving the schedulinginformation, the terminal immediately stops the DRX retransmission timerand starts the HARQ RTT timer again. The above operation continues untilthe packet is successfully received (1 c-35).

FIG. 1D illustrates a frame structure in which the terminal schematizesa data transmission in a configured uplink transmission according to anembodiment of the disclosure.

In general, in a cellular-based wireless communication system, in orderfor the terminal within the base station to transmit uplink data, theterminal receives signaling indicating an uplink resource allocationfrom the base station and transmits data to the allocated uplinkresource. In the LTE, the signaling indicating the uplink resourceallocation receives the corresponding information from a physicalchannel called a physical dedicated control channel (PDCCH), and thePDCCH includes physical uplink shared channel (PUSCH) resourceinformation that can transmit data.

Meanwhile, in this exemplified drawing, a scenario in which the terminalreceives, from the base station, a configuration of a resource which canperiodically transmit uplink data without receiving the above PDCCH bythe message of the RRC layer is assumed. This scenario can be applied todownlink and uplink respectively, and in this drawing, only the uplinkis described for convenience of explanation. The scenario oftransmitting the downlink periodically without receiving the PDCCH iscalled ‘downlink has been configured’ in the terminal, and the scenarioof transmitting the uplink periodically without receiving the PDCCH tobe described below is called ‘uplink has been configured’ in theterminal.

The length of time for the resource to which the uplink data can betransmitted may be an OFDM symbol, a slot, and a subframe unit. In thisexemplified drawing, the scenario configured in slot units is assumed,and thus it is assumed that resources 1 d-03, 1 d-13, 1 d-23, 1 d-33, 1d-43, 1 d-53, 1 d-63, 1 d-73, and 1 d-83 through which the terminal cantransmit new uplink data are slots.

On the other hand, when the above periodic uplink data is transmitted,the HARQ process identifier for each new transmission identifies whatdata is transmitted in the case in which the corresponding dataretransmission is required. The above HARQ process identifier is not aninfinite number, and therefore the same HARQ process identifier can bereused for subsequent new data transmission. The HARQ process identifieris determined by the OFDM symbol, the slot, and the subframe identifierat the time when the terminal transmits the uplink data. For example, itcan be determined as in the following Equation.HARQ Process ID=[floor (current symbol identifier/cycle of configureduplink allocation)] modulo numberOfConfGrant−Processes (the number ofprocesses of configured uplink of terminal that base station configures)

In this exemplified drawing, the scenario in which the resources 1 d-03,1 d-33, and 1 d-63 have the same HARQ process identifiers (e.g.,identifier #1), and the resources 1 d-13, 1 d-43, and 1 d-73 have thesame HARQ process identifier (e.g., identifier #2), and the resources 1d-23, 1 d-53, and 1 d-83 have the same HARQ process identifiers may beconsidered (for example, identifier #3).

At this time, whenever each new transmission is performed, the terminalstarts a timer called configuredGrantTimer (1 d-05), (1 d-15), (1 d-25)for each process. If the retransmission to this process is made, theconfiguredGrantTimer is to prevent the retransmission from beingretransmitted to the corresponding process until the retransmission iscomplete. Accordingly, when the data transmission is performed in theslot (1 d-03), the configuredGrantTimer is started (1 d-05), and whenthe timer is started, the terminal monitors the PDCCH to determinewhether the retransmission to the corresponding HARQ process is made. Ifthe terminal receives the allocation (PDCCH) for retransmission (1 d-07)as the HARQ process identifier used in the (1 d-03) while theconfiguredGrantTimer is being started, the terminal restarts (re-drives)the configuredGrantTimer (1 d-09).

Thereafter, since the configuredGrantTimer is started by the (1 d-09) inthe (1 d-33) slot using the same HARQ identifier as in the above (1d-03), the terminal does not perform a new transmission in thecorresponding (1 d-33) slot for the completion of the retransmission inthe step (1 d-03). If the PDCCH is not received for the retransmissionfor the corresponding HARQ process identifier until theconfiguredGrantTimer expires, the terminal can perform a new datatransmission upon arrival of a new transmission slot for thecorresponding HARQ process identifier (1 d-63).

Meanwhile, it can be assumed the scenario that the DRX described in FIG.1C and the configured uplink transmission described in FIG. 1D aresimultaneously set in the terminal. When the DRX is configured asdescribed above, the active time is defined as the following time periodduring which the terminal needs to monitor the PDCCH transmitted fromthe base station. In one example, the active time is defined whendrx-onDurationTimer or drx-InactiveTimer, drx-RetransmissionTimerDL,drx-RetransmissionTimerUL, or ra-ContentionResolutionTimer is activated.In another example, the active time is defined when the above timer isstill pended by transmitting a scheduling request to the base station.In yet another example, the active time is defined when a random accessresponse for a random access preamble that the terminal does not selectdirectly is received and then PDCCH allocated to the C-RNTI of theterminal was not received from the base station.

When the DRX is set in the terminal as described above, the terminalmonitors the PDCCH when the drx-RetransmissionTimerDL or thedrx-RetransmissionTimerUL timer is started for the HARQ process in orderto monitor the scheduling information for the retransmission. Thedrx-RetransmissionTimerDL or the drx-RetransmissionTimerUL timer startswhen drx-HARQ-RTT-TimerDL or drx-HARQ-RTT-TimerUL expires, respectively.

Meanwhile, the drx-HARQ-RTT-TimerDL or a drx-HARQ-RTT-TimerUL timerstarts when the terminal allocates a resource for a new transmission onthe downlink or the uplink when the terminal monitors the PDCCH in theactive time. When the base station allocates the resource to theterminal in the configured uplink or downlink, if the correspondingcycle is aligned with the drx-onDurationTimer, the terminal alwaystransmits a new transmission in accordance with the correspondingdrx-onDurationTimer for the configured uplink/downlink (that is,performs the new transmission in the active time), and therefore whenthe corresponding transmission fails and thus the retransmission isrequired, the drx-HARQ-RTT-TimerDL or the drx-HARQ-RTT-TimerUL timerstarts to drive the drx-RetransmissionTimerDL or thedrx-RetransmissionTimerUL timer and the terminal may perform the PDCCHmonitoring for the retransmission.

However, the base station may not configure the downlink/uplink and thedrx-onDurationTimer configured in this way. For example, when theconfigured downlink/uplink are short, the DRX cycle itself becomes tooshort, and the effect of reducing the power consumption may become toosmall. In other words, the base station can configure the configureduplink having a short cycle to reduce the transmission delay even whenthe terminal does not always have data to be transmitted. At this time,since the terminal can use the configured uplink of the set short cycleonly if there is data to be transmitted, in this case, the base stationcan be configured in the terminal simultaneously with the DRX. In thiscase, however, it may be undesirable to set the DRX cycle too short(i.e., to set the drx-onDurationTimer to be too short) because ofincreasing the power consumption of the terminal.

Accordingly, the disclosure provides that the terminal always starts thedrx-HARQ-RTT-TimerDL for the corresponding HARQ process in thecorresponding configured resources when the downlink and DRX configuredas described above are simultaneously set. At this time, the starttiming receives data on the PDSCH from the configured downlink, andstarts immediately after transmitting to the PUCCH ACK/NACK informationwhich is a response thereto.

In addition, in the disclosure, when the uplink and DRX configured asdescribed above are simultaneously set, the terminal always starts thedrx-HARQ-RTT-TimerUL for the corresponding HARQ process when there isdata to be transmitted on the uplink in the corresponding configuredresource. At this time, the start timing starts immediately after thedata is transmitted on the PUSCH from the configured uplink. If the datais repeatedly transmitted on the uplink, the drx-HARQ-RTT-TimerUL startsimmediately after the first transmission among the repeatedtransmission.

Accordingly, even if the terminal is not in the Active Time, theterminal can start the drx-HARQ-RTT-TimerDL or drx-HARQ-RTT-TimerULtimer, and if the timers expire, the drx-RetransmissionTimerDL ordrx-RetransmissionTimerUL timer is started, so the terminal may monitorthe PDCCH for the retransmission when the data transmission/reception onthe configured downlink/uplink fail.

FIG. 1E illustrates an operation sequence of the terminal when DRX and aconfigured downlink/uplink transmission according to an embodiment ofthe disclosure are simultaneously set.

In the exemplified drawings, the RRC_CONNECTED state in which theterminal is connected to the base station is assumed (1 e-01). Then, theterminal receives the DRX configuration and the configured downlinkand/or uplink transmission related configuration information from thebase station through the RRC message (1 e-03). For example, the RRClayer message may be an RRCConnectionReconfiguration message.

The DRX is a technique of adjusting the time for monitoring the PDCCH toreduce power consumption of the terminal as described above, and theconfigured uplink is a technique of periodically transmitting new datawithout PDCCH. There are two types (Type 1 and Type 2) in the configureduplink. Type 1 is activated simultaneously with RRC reception (i.e., (1e-05) step is unnecessary). In the case of Type 2, a separate activationcommand and inactivation command are required on the PDCCH after the RRCreception. The DRX configuration and the configuration for theconfigured uplink can be received through the same RRC message ordifferent RRC messages respectively.

Thereafter, as described above, in the case of the Type 2, theactivation command may be received on the PDCCH (1 e-05), and thereceived configuration may be activated to periodically perform theuplink data transmission.

Thereafter, the terminal can perform new data transmission of theconfigured uplink according to the configured cycle information.

If the configured downlink and DRX are simultaneously configured, theterminal always starts the drx-HARQ-RTT-TimerDL for the correspondingHARQ process (1 e-11), when a new transmission cycle of thecorresponding configured resource arrives (1 e-09). At this time, thestart timing receives data on the PDSCH from the configured downlink,and starts immediately after transmitting to the PUCCH ACK/NACKinformation which is a response thereto.

In addition, if the configured uplink and DRX are simultaneouslyconfigured, the terminal always starts the drx-HARQ-RTT-TimerUL for thecorresponding HARQ process (1 e-11), when a new transmission cycle ofthe corresponding configured resource arrives, in fact, when there isdata to be transmitted to the uplink (1 e-09). At this time, the starttiming starts immediately after the data is transmitted on the PUSCHfrom the configured uplink. If the data is repeatedly transmitted on theuplink, the drx-HARQ-RTT-TimerUL starts immediately after the firsttransmission among the repeated transmission.

Accordingly, even if the terminal is not in the Active Time, theterminal can start the drx-HARQ-RTT-TimerDL or drx-HARQ-RTT-TimerULtimer, and if the drx-HARQ-RTT-TimerDL or drx-HARQ-RTT-TimerUL timersexpire (1 e-13), the drx-RetransmissionTimerDL ordrx-RetransmissionTimerUL timer is driven, so the terminal may monitorthe PDCCH for the retransmission when the data transmission/reception onthe configured downlink/uplink fails (1 e-15).

FIG. 1F illustrates a configuration of the terminal according to anembodiment of the disclosure.

Referring to FIG. 1F, the terminal includes a radio frequency (RF)processor 1 f-10, a baseband processor 1 f-20, a memory 1 f-30, and acontroller 1 f-40.

The RF processor 1 f-10 serves to transmit and receive a signal througha radio channel, such as band conversion and amplification of a signal.That is, the RF processor 1 f-10 may up-convert a baseband signalprovided from the baseband processor 1 f-20 into an RF band signal andthen transmit the RF band signal through an antenna and down-convert theRF band signal received through the antenna into the baseband signal.For example, the RF processor 1 f-10 may include a transmitting filter,a receiving filter, an amplifier, a mixer, an oscillator, a digital toanalog converter (DAC), an analog to digital converter (ADC), or thelike. FIG. 1F illustrates only one antenna but the terminal may includea plurality of antennas.

Further, the RF processor 1 f-10 may include a plurality of RF chains.Further, the RF processor 1 f-10 may perform beamforming. For thebeamforming, the RF processor 1 f-10 may adjust a phase and a size ofeach of the signals transmitted and received through a plurality ofantennas or antenna elements.

The baseband processor 1 f-20 performs a conversion function between abaseband signal and a bit string according to a physical layer standardof a system. For example, when data are transmitted, the basebandprocessor 1 f-20 generates complex symbols by coding and modulating atransmitted bit string. Further, when data are received, the basebandprocessor 1 f-20 recovers the received bit string by demodulating anddecoding the baseband signal provided from the RF processor 1 f-10. Forexample, according to the orthogonal frequency division multiplexing(OFDM) scheme, when data are transmitted, the baseband processor 1 f-20generates the complex symbols by coding and modulating the transmittedbit string, maps the complex symbols to sub-carriers, and then performsan inverse fast Fourier transform (IFFT) operation and a cyclic prefix(CP) insertion to construct the OFDM symbols.

Further, when data are received, the baseband processor 1 f-20 dividesthe baseband signal provided from the RF processor 1 f-10 in an OFDMsymbol unit and recovers the signals mapped to the sub-carriers by afast Fourier transform (FFT) operation and then recovers the receivedbit string by the demodulation and decoding.

The baseband processor 1 f-20 and the RF processor 1 f-10 transmit andreceive a signal as described above. Therefore, the baseband processor 1f-20 and the RF processor 1 f-10 may be called a transmitter, areceiver, a transceiver, or a communication interface. Further, at leastone of the baseband processor 1 f-20 and the RF processor 1 f-10 mayinclude different communication modules to process signals in differentfrequency bands. Further, the different frequency bands may include asuper high frequency (SHF) (for example: 2.5 GHz, 5 GHz) band, amillimeter wave (for example: 60 GHz) band.

The memory 1 f-30 stores data such as basic programs, applicationprograms, and configuration information for the operation of theterminal.

The controller 1 f-40 controls the overall operations of the terminal.For example, the controller 1 f-40 transmits and receives a signalthrough the baseband processor 1 f-20 and the RF processor 1 f-10.Further, the controller 1 f-40 records and reads data in and from thememory 1 f-30. For this purpose, the controller 1 f-40 may include atleast one processor. For example, the controller 1 f-40 may include acommunication processor (CP) performing a control for communication andan application processor (AP) controlling an upper layer such as theapplication programs.

According to the embodiment of the disclosure, the controller 1 f-40includes a multi-link processor 1 f-42 that performs the processing tobe operated in a multi-link mode. For example, the controller 1 f-40 maycontrol the terminal to perform the procedure illustrated in theoperation of the terminal illustrated in FIG. 1F.

According to the embodiment of the disclosure, the terminal drives HARQRTT Timers according to the above-described conditions according to theDRX configuration information and the configured downlink/uplinktransmission information configured from the base station, and whenretransmission is required, the terminal may monitor the PDCCH at thecorresponding timing to receive the retransmission-related schedulinginformation.

Second Embodiment

FIG. 2A illustrates a structure of an LTE system according to anotherembodiment of the disclosure.

As illustrated in FIG. 2A, a radio access network of an LTE system isconfigured to include next generation base stations (evolved node B,hereinafter, eNB, Node B, or base station) 2 a-05, 2 a-10, 2 a-15, and 2a-20, a mobility management entity (MME) 2 a-25, and a serving-gateway(S-GW) 2 a-30. User equipment (hereinafter, UE or terminal) 2 a-35accesses an external network through the eNBs 2 a-05, 2 a-10, 2 a-15,and 2 a-20 and the S-GW 2 a-30.

In FIG. 2A, the eNBs 2 a-05 to 2 a-20 correspond to the existing node Bof the UMTS system. The eNB 2 a-05 is connected to the UE 2 a-35 througha radio channel and performs more complicated role than the existingnode B. In the LTE system, in addition to a real-time service like avoice over Internet protocol (VoIP) through the Internet protocol, allthe user traffics are served through a shared channel and therefore anapparatus for collecting and scheduling status information such as abuffer status, an available transmission power status, and a channelstatus of the terminals is required. Here, the eNBs 2 a-05, 2 a-10, 2a-15, and 2 a-20 take charge of the collecting and scheduling. One eNBgenerally controls a plurality of cells.

For example, to implement a transmission rate of 100 Mbps, the LTEsystem uses, as a radio access technology, orthogonal frequency divisionmultiplexing (hereinafter, OFDM) scheme in, for example, a bandwidth of20 MHz. Further, an adaptive modulation and coding (hereinafter,referred to as AMC) scheme determining a modulation scheme and a channelcoding rate according to a channel status of the terminal is applied.The S-GW 2 a-30 is an apparatus for providing a data bearer andgenerates or removes the data bearer according to the control of the MME2 a-25. The MME 2 a-25 is a device for performing various controlfunctions as well as a mobility management function for the terminals 2a-35 and is connected to a plurality of base stations 2 a-05, 2 a-10, 2a-15 and 2 a-20.

FIG. 2B illustrates a radio protocol structure in the LTE systemaccording to another embodiment of the disclosure.

Referring to FIG. 2B, the radio protocol of the LTE system is configuredto include packet data convergence protocols (PDCPs) 2 b-05 and 2 b-40,radio link controls (RLCs) 2 b-10 and 2 b-35, and medium access controls(MACs) 2 b-15 and 2 b-30, respectively, in the terminal and the eNB. ThePDCPs 2 b-05 and 2 b-40 are in charge of operations such as IP headercompression/decompression. The main functions of the PDCP are summarizedas follows: header compression and decompression function (headercompression and decompression: ROHC only); transfer function of userdata (transfer of user data); in-sequence delivery function (in-sequencedelivery of upper layer PDUs at PDCP re-establishment procedure for RLCAM); reordering function (For split bearers in DC (only support for RLCAM): PDCP PDU routing for transmission and PDCP PDU reordering forreception); duplicate detection function (duplicate detection of lowerlayer SDUs at PDCP re-establishment procedure for RLC AM);retransmission function (retransmission of PDCP SDUs at handover and,for split bearers in DC, of PDCP PDUs at PDCP data-recovery procedure,for RLC AM); ciphering and deciphering function (ciphering anddeciphering); and/or timer-based SDU discard function (timer-based SDUdiscard in uplink).

The radio link controls (hereinafter, referred to as RLCs) 2 b-10 and 2b-35 reconfigures the PDCP packet data unit (PDU) to an appropriate sizeto perform the ARQ operation or the like. The main functions of the RLCare summarized as follows: data transfer function (transfer of upperlayer PDUs); ARQ function (error correction through ARQ (only for AMdata transfer)); concatenation, segmentation, reassembly functions(concatenation, segmentation and reassembly of RLC SDUs (only for UM andAM data transfer)); re-segmentation function (re-segmentation of RLCdata PDUs (only for AM data transfer)); reordering function (reorderingof RLC data PDUs (only for UM and AM data transfer); duplicate detectionfunction (duplicate detection (only for UM and AM data transfer)); errordetection function (protocol error detection (only for AM datatransfer)); RLC SDU discard function (RLC SDU discard (only for UM andAM data transfer)); and/or RLC re-establishment function (RLCre-establishment).

The MACs 2 b-15 and 2 b-30 are connected to several RLC layer entitiesconfigured in one terminal and perform an operation of multiplexing RLCPDUs into an MAC PDU and demultiplexing the RLC PDUs from the MAC PDU.The main functions of the MAC are summarized as follows.

mapping function (mapping between logical channels and transportchannels);

multiplexing/demultiplexing function (multiplexing/demultiplexing of MACSDUs belonging to one or different logical channels into/from transportblocks (TB) delivered to/from the physical layer on transport channels);scheduling information reporting function (scheduling informationreporting); HARQ function (Error correction through HARQ); priorityhandling function between logical channels (priority handling betweenlogical channels of one UE); priority handling function betweenterminals (priority handling between UEs by means of dynamicscheduling); MBMS service identification function (MBMS serviceidentification); transport format selection function (transport formatselection); and/or padding function (padding).

Physical layers 2 b-20 and 2 b-25 perform an operation of channel-codingand modulating upper layer data, making the upper layer data as an OFDMsymbol and transmitting them to a radio channel, or demodulating andchannel-decoding the OFDM symbol received through the radio channel andtransmitting the demodulated and channel-decoded OFDM symbol to theupper layer.

FIG. 2C illustrates a structure of a next generation mobilecommunication system according to another embodiment of the disclosure.

Referring to FIG. 2C, a radio access network of a next generation mobilecommunication system (hereinafter referred to as NR or 5G) is configuredto include a next generation base station (new radio node B, hereinafterNR NB or NR gNB) 2 c-10 and a new radio core network (NR CN) 2 c-05. Theuser terminal (new radio user equipment, hereinafter, NR UE or terminal)2 c-15 accesses the external network through the NR gNB 2 c-10 and theNR CN 2 c-05.

In FIG. 2C, the NR gNB 2 c-10 corresponds to an evolved node B (eNB) ofthe existing LTE system. The NR gNB 2 c-10 is connected to the NR UE 2c-15 via a radio channel and may provide a service superior to theexisting node B.

In the next generation mobile communication system, since all usertraffics are served through a shared channel, an apparatus forcollecting status information such as a buffer status, an availabletransmission power status, and a channel status of the UEs to performscheduling is required. The NR gNB 2 c-10 may serve as the device. OneNR gNB generally controls a plurality of cells. In order to realize thehigh-speed data transmission compared with the existing LTE, the NR gNBmay have the existing maximum bandwidth or more, and may be additionallyincorporated into a beam-forming technology by using orthogonalfrequency division multiplexing (hereinafter, referred to as OFDM)scheme as a radio access technology.

Further, an adaptive modulation and coding (hereinafter, referred to asAMC) scheme determining a modulation scheme and a channel coding rateaccording to a channel status of the terminal is applied. The NR CN 2c-05 may perform functions such as mobility support, bearer setup, QoSsetup, and the like. The NR CN 2 c-05 is a device for performing amobility management function for the terminal and various controlfunctions and is connected to a plurality of base stations. In addition,the next generation mobile communication system can interwork with theexisting LTE system, and the NR CN 2 c-05 is connected to the MME 2 c-25through the network interface. The MME 2 c-25 is connected to the eNB 2c-30 which is the existing base station.

FIG. 2D illustrates a radio protocol structure of a next generationmobile communication system according to an embodiment of thedisclosure.

Referring to FIG. 2D, the radio protocol of the next generation mobilecommunication system is configured to include NR PDCPs 2 d-05 and 2d-40, NR RLCs 2 d-10 and 2 d-35, and NR MACs 2 d-15 and 2 d-30,respectively, in the terminal and the NR base station. The mainfunctions of the NR PDCPs 2 d-05 and 2 d-40 may include some of thefollowing functions: header compression and decompression function(header compression and decompression: ROHC only); transfer function ofuser data (transfer of user data); in-sequence delivery function(in-sequence delivery of upper layer PDUs); reordering function (PDCPPDU reordering for reception); duplicate detection function (duplicatedetection of lower layer SDUs); retransmission function (retransmissionof PDCP SDUs); ciphering and deciphering function (ciphering anddeciphering); and/or timer-based SDU discard function (timer-based SDUdiscard in uplink).

In this case, the reordering function of the NR PDCP apparatus refers toa function of reordering PDCP PDUs received in a lower layer in orderbased on a PDCP sequence number (SN) and may include a function oftransferring data to the upper layer in the reordered order, a functionof recording PDCP PDUs lost by the reordering, a function of reporting astate of the lost PDCP PDUs to a transmitting side, and a function ofrequesting a retransmission of the lost PDCP PDUs.

The main functions of the NR RLCs 2 d-10 and 2 d-35 may include some ofthe following functions: data transfer function (transfer of upper layerPDUs); in-sequence delivery function (in-sequence delivery of upperlayer PDUs); out-of-sequence delivery function (out-of-sequence deliveryof upper layer PDUs); ARQ function (error correction through ARQ);concatenation, segmentation, reassembly function (concatenation,segmentation and reassembly of RLC SDUs); re-segmentation function(re-segmentation of RLC data PDUs); reordering function (reordering ofRLC data PDUs); duplicate detection function (duplicate detection);error detection function (protocol error detection); RLC SDU discardfunction (RLC SDU discard); and/or RLC re-establishment function (RLCre-establishment).

In the above description, the in-sequence delivery function of the NRRLC apparatus refers to a function of delivering RLC SDUs received froma lower layer to an upper layer in order, and may include a function ofreassembling and delivering an original one RLC SDU which is dividedinto a plurality of RLC SDUs and received, a function of rearranging thereceived RLC PDUs based on the RLC sequence number (SN) or the PDCPsequence number (SN), a function of recording the RLC PDUs lost by thereordering, a function of reporting a state of the lost RLC PDUs to thetransmitting side, and a function of requesting a retransmission of thelost RLC PDUs.

In the above description, the in-sequence delivery function of the NRRLC apparatus may include a function of in sequence delivering, to theupper layer, only the RLC SDUs before the lost RLC SDU when there is thelost RLC SDU, a function of in sequence delivering, to the upper layer,all the RLC SDUs received before the timer starts when the predeterminedtimer expires even though there is the lost RLC SDU, or a function of insequence delivering, to the upper layer, all the RLC SDUs received untilnow if the predetermined timer expires even if there is the lost RLCSDU.

Further, the NR RLC may process the RLC PDUs in the received order (inorder of arrival regardless of the order of a sequence number and thesequence number), and may deliver the processed RLC PDUs to the PDCPentity the out-of-sequence delivery. In the case of the segment, the NRRLC may receive the segments which are stored in the buffer or is to bereceived later and reconfigure the RLC PDUs into one complete RLC PDUand then deliver the complete RLC PDU to the PDCP entity. The NR RLClayer may not include the concatenation function and may perform thefunction in the NR MAC layer or may be replaced by the multiplexingfunction of the NR MAC layer.

In this case, the out-of-sequence delivery function of the NR RLCapparatus refers to a function of directly delivering the RLC SDUsreceived from the lower layer to the upper layer regardless of order.Originally, when one RLC SDU is split into several RLC SDUs andreceived, the out-of-sequence delivery function of the NR RLC apparatusmay include a function of reassembling and delivering the RLC SDUs andmay include a function of storing the RLC SNs or the PDCP SNs of thereceived RLC PDUs and ordering the RLC SNs or the PDCP SNs to record thelost RLC PDUs.

The NR MACs 2 d-15 and 2 d-30 may be connected to several NR RLC layerapparatus configured in one terminal, and the main functions of the NRMAC may include some of the following functions: mapping function(mapping between logical channels and transport channels); multiplexingand demultiplexing function (multiplexing/demultiplexing of MAC SDUs);scheduling information reporting function (scheduling informationreporting); HARQ function (error correction through HARQ); priorityhandling function between logical channels (priority handling betweenlogical channels of one UE); priority handling function betweenterminals (priority handling between UEs by means of dynamicscheduling); MBMS service identification function (MBMS serviceidentification); transport format selection function (transport formatselection); and/or padding function (padding).

The NR PHY layers 2 d-20 and 2 d-25 may perform an operation ofchannel-coding and modulating upper layer data, making the upper layerdata as an OFDM symbol and transmitting them to a radio channel, ordemodulating and channel-decoding the OFDM symbol received through theradio channel and transmitting the demodulated and channel-decoded OFDMsymbol to the upper layer.

FIG. 2E illustrates a scenario in which a bandwidth part is applied inthe next generation mobile communication system according to anembodiment of the disclosure.

A bandwidth part (BWP) application technology means that a terminalperforms communication using only some bandwidths of system bandwidthsused by one cell. Essentially, the NR may support a wide range offrequency bands (e.g., 400 MHz bandwidth) compared to the LTE, so it canbe a burden on implementation for the terminal which meet all of thesystem's frequency bandwidths, and for some terminals, there may be noproblem in supporting only a small range of frequency bandwidth. The BWPis used to reduce the manufacturing cost of the terminal or to savepower of the terminal. The BWP may be configured by the base stationonly for the terminal supporting the purpose.

Referring to FIG. 2E, there are largely three BWP operating scenarios inthe NR.

A first scenario is to apply the BWP for the terminal that supports onlya frequency bandwidth 2 e-10 narrower than a system bandwidth 2 e-05used by one cell. To reduce the manufacturing cost, a specific terminalmay be developed to support a limited bandwidth. The terminal needs toreport to the base station supporting only the limited bandwidth, andaccordingly, the base station configures the maximum bandwidth or lessBWP supported by the terminal.

A second scenario is to apply the BWP for terminal power saving. Forexample, one terminal performs communication using the entire systembandwidth 2 e-15 or a partial bandwidth 2 e-20 used by one cell, but thecommunication base station may set a narrower bandwidth 2 e-25 for thesaving purpose.

A third scenario is to apply individual BWPs corresponding to differentnumerologies. The numerology means that a physical layer configurationis diversified in order to implement optimal data transmission accordingto various service requirements. For example, in an OFDMA structurehaving a plurality of subcarriers, a separation distance between thesubcarriers may be variably adjusted according to a predeterminedrequirement. One terminal may communicate by applying a plurality ofnumerologies at the same time. At this time, since the physical layerconfiguration corresponding to each numerology is described above, it ispreferable to divide and apply each numerology into separate BWPs 2 e-35and 2 e-40.

Since a supportable bandwidth is different for each terminal in the NR,in initial access, communication may be performed with primary BWPapplicable to all terminals and the BWP for a specific terminal isapplied from a predetermined point in time. The applied BWP may bechanged through predetermined signaling and the BWP to be applied in thetarget cell at the time of handover is indicated to the UE through thepredetermined signaling. In addition, the BWP timer may exist to specifythe use of a particular BWP for the above terminal and may be deliveredby the RRC signaling.

This timer means the operation of stopping the use of the configured BWPif there is no use of the activated BWP and returning to the initialapplied primary BWP. The BWP switching operation through the above BWPtimer can be configured by the base station for the purpose of fallbackoperation of appropriate BWP and reduction of terminal power.

FIG. 2F illustrates a diagram for applying an additional uplinkfrequency according to an embodiment of the disclosure.

In the mobile communication system, a mismatch of a service area mayoccur on the uplink and the downlink. The mismatch may occur due todifferences in the channel characteristics of the uplink and thedownlink, or due to a limitation of the maximum transmission power ofthe terminal or a structural limitation of the transmission antenna.Typically, the service area of the downlink is wider than the servicearea of the uplink. For example, in the 3.5 GHz TDD system, the servicearea 2 f-05 of the downlink is wider than the service area 2 f-10 of theuplink. In this case, the first terminal 2 f-20 has no problem inreceiving the service on the uplink and the downlink, but the secondterminal 2 f-25 has a problem in successfully transmitting the data tothe base station 2 f-15 on the uplink.

Therefore, in order to eliminate the problem due to the mismatch, theeffective service area of the downlink is reduced to match between theservice area of the downlink and the service area of the uplink. Thatis, although a wider service area may be provided on the downlink, theservice area of the uplink is limited.

In the next generation mobile communication system, in order to solvethe performance limitation due to such mismatch, the terminal may applythe uplink frequency having a wider service area. For example, an uplinkof 3.5 GHz and a separate uplink 2 f-30 of 1.8 GHz are additionallyprovided to the terminal. The additional uplink frequency is referred toas a supplementary uplink (SUL) frequency.

Due to the frequency characteristics, the lower the frequency band, thelonger the radio signal propagation distances. Thus, 1.8 GHz, which islower than 3.5 GHz enables a wider service area. Accordingly, the secondterminal 2 f-50 may successfully transmit data to the base station 2f-40 using the uplink 2 f-35 of 1.8 GHz. In addition, the first terminal2 f-45 is not related to the service area problem. However, since boththe 1.8 GHz and 3.5 GHz uplinks can be used, one of the 1.8 GHz and 3.5GHz uplinks may be selected and used for the purpose of dispersing theaccess congestion of the uplink. The additional uplink frequency may bean LTE frequency.

Both the NR uplink frequency and the SUL frequency can be set for oneterminal. At this time, the uplink data channel PUSCH can be transmittedon only one uplink at a time. The PUCCH is also transmitted on only oneuplink at a time, and may be transmitted in the same or different uplinkas or to the PUSCH.

The base station supporting the SUL provides a first threshold valuerequired for determining the uplink on which random access is attemptedto terminals in the cell using system information. The terminalsupporting the SUL measures a sync signal block (SSB) broadcasted by thebase station on the downlink to derive RSRP and compares the derivedRSRP with the first threshold value. If the measured downlink channelquality is lower than the first threshold value, the terminal selectsthe SUL frequency on an uplink on which random access is attempted.Otherwise, the terminal performs random access at the NR uplinkfrequency.

In the embodiment of the disclosure, the operation related to variousBWPs introduced in the NR, in particular, the BWP switching operationwill be described. The BWP can be largely classified into three types.First, there is a first BWP that can be defined as a first BWP or aninitial BWP. The first BWP includes the system information, inparticular, the configuration information of the first BWP applied forinitial access to the MSI. The configuration information of the BWPincludes a center frequency, frequency bandwidth information, and randomaccess radio resource information. At this time, the center frequencyand the bandwidth information may be separately indicated on the uplinkand the downlink. The random access radio resource may be within atleast the frequency bandwidth. The frequency bandwidth information canbe indicated in PRB number or units of Hz. As another example, thedownlink configuration information of the first BWP may follow that ofthe MSI. In this case, the MSI does not need to separately include theconfiguration information of the first BWP, or includes only the uplinkfrequency information and the random access radio resource information.

The initial connection operation and communication are performed throughthe first BWP, and the terminal also receives a predetermined RRCcontrol message from the base station using the first BWP. In the RRCmessage, a list of a plurality (up to four BWPs per serving cell) ofBWPs supported by the corresponding serving cell and valid BWP timerinformation for the corresponding serving cell are provided, and the BWPconfiguration included in the corresponding list includes a BWP indexand specific BWP configuration information. That is, the base stationcan be instructed by the uplink and downlink for each BWP informationincluding the center frequency and frequency bandwidth information forthe BWPs supported by the corresponding serving cell in the RRC message.The frequency bandwidth does not exceed the maximum frequency bandwidthincluded in the capability information of the terminal.

In addition, among the BWPs included in the BWP list, the base stationmay include an indicator indicating the second BWP and the third BWP.The second BWP is defined as a primary BWP or a default BWP, and is afallback BWP in which the terminal operates as another BWP in thecorresponding serving cell and is operated by returning if the BWP timerexpires. Also, the third BWP means a BWP in which the base station isinitially activated through the RRC configuration among the plurality ofBWPs. The second BWP and the third BWP may be set to the same BWP andmay be set to different BWPs.

If the terminal supports a plurality of Numerologies, and the basestation desires to set a BWP according to Numerology, the RRC controlmessage includes configuration information for a plurality of BWPs. TheBWP can move the center frequency at predetermined time intervalsaccording to a predetermined pattern while maintaining the samebandwidth. This is called frequency hopping, and the pattern informationand information indicating whether to perform the pattern informationmay be included in the configuration information. An indicator foractivating the configured downlink and uplink BWPs may be included inthe RRC control message or may include a control message triggering theactivation of the corresponding BWP in the downlink control information(DCI) of the physical downlink control channel (PDCCH).

Also, in the disclosure, it is divided depending on whether the uplinkBWP and the downlink BWP exist in the same frequency band, that is,whether the uplink and downlink BWPs are time division multiplexing(TDM) or frequency division multiplexing (FDM). If the uplink BWP andthe downlink BWP are FDMed, that is, if the uplink BWP and the downlinkBWP are activated in different frequency bands, the uplink/downlinkoperates in a paired spectrum, and if the uplink BWP and the downlinkBWP are TDMed, that is, if the uplink BWP and the downlink BWP areactivated with time difference in the same frequency band, theuplink/downlink operates in the unpaired spectrum. The followingdescription of the disclosure will be made on the basis of the abovedefinition and operation.

FIG. 2G illustrates a diagram for describing a bandwidth part switchingoperation in a general serving cell according to an embodiment of thedisclosure. 2 g-05 is a diagram for the case in which theuplink/downlink operates in the paired spectrum, and a downlinkfrequency f1+delta of 2 g-10 and an uplink frequency f1 of 2 g-15 showsa difference in a frequency domain by delta and is configured andactivated. On the other hand, 2 g-20 is a diagram for the case in whichthe uplink/downlink operates in the unpaired spectrum, and a downlinkfrequency f2 of 2 g-25 and an uplink frequency f2 of 2 g-30 isconfigured and activated in the same frequency domain and the BWP areais divided in the time area.

In the above two cases, the operation when the terminal is instructed toperform uplink/downlink scheduling, i.e., BWP switching, can besummarized as shown in the following table.

TABLE 2 UL/DL BWP switching operation when one uplink exists Pairedspectrum Unpaired spectrum Downlink Instruct switching to the Instructswitching to the scheduling corresponding BWP, including correspondingBWP, specific BWP index in DCI 1 for including specific BWP downlinkscheduling => index in DCI 1 for Switch to BWP indicated downlinkscheduling => only by downlink BWP and Switch both of downlink maintainuplink BWP into BWP and linked uplink current configuration BWP toindicated BWP Uplink Instruct switching to the Instruct switching to thescheduling corresponding BWP, including corresponding BWP, specific BWPindex in DCI 0 for including specific BWP uplink scheduling => index inDCI 0 for uplink Switch to BWP indicated scheduling => Switch both onlyby uplink BWP and of uplink BWP and linked maintain downlink BWP intodownlink BWP to indicated current configuration BWP

In addition, if the terminal is operating at the third BWP and then theBWP timer (BWP-inactivityTimer) expires, the operation to make thefallback to the second BWP can be summarized by being classified intothe case in which the uplink/downlink is operating in the pairedspectrum and the case in which the uplink/downlink is operating in theunpaired spectrum.

For the above two cases, the BWP switching operation of the terminalwhen the BWP timer of the terminal expires can be summarized as shown inthe table below.

TABLE 3 Operation when BWP timer expires in case in which one uplinkexists Paired spectrum Unpaired spectrum Bwp- When DCI 1 for downlinkWhen DCI 1 for downlink inactivity scheduling is received and thescheduling or DCI 0 for Timer start corresponding DCI indicates uplinkscheduling is (BWP timer second BWP other than third received and thestart) BWP, Bwp-inactivityTimer corresponding DCI starts indicatessecond BWP other than third BWP, Bwp-inactivityTimer starts Upon expiryDownlink: Switch to second Downlink: Switch to of BWP of downlinkalready second BWP of downlink Bwp- configured already configuredinactivity Uplink: Maintain operation in Uplink: Switch to second Timeruplink BWP currently BWP of uplink already (BWP timer activatedconfigured expires)

2 g-35 is a drawing for describing the timing relationship between theuplink-downlink of the terminal, 2 g-40 indicates an i-th downlink frameof the terminal, and 2 g-45 indicates an i-th uplink frame of theterminal.

In this case 2 g-50, the timing advance between the downlink and theuplink is defined as T_(TA)=(N_(TA)+N_(TA,offset))T_(c). Here, N_(TA)means an offset between the radio frames of the uplink and the downlink,and N_(TA offset) is a fixed value corresponding to the time for theterminal to switch from the uplink to the downlink. The N_(TA offset)value is 0 for frequency division duplex (FDD), and has different valuesaccording to the frequency band only for time division duplex (TDD), andis defined as N_(TA_offset)=624·64/2^(μ). Here, μ represents the valueof the supporting transfer numerology and has the following tablevalues.

TABLE 4 NR numerology μ Δf = 2^(μ) · 15 [kHz] Cyclic prefix 0 15 Normal1 30 Normal 2 60 Normal, Extended 3 120 Normal 4 240 Normal

In addition, the above T_(c)=1/(Δf_(max)·Nf) is a minimum value in thetime domain in NR, and is a time value for confirming an OFDM symbolwithin a range without oversampling.

In summary, if all the serving cells of the same time advance group(TAG) operate in the uplink/downlink paired spectrum, the N_(TA offset)of the corresponding serving cell has a value of zero. On the otherhand, if there is at least one serving cell operating in theuplink/downlink unpaired spectrum in the same time advance group (TAG),the serving cell has a value of N_(TA_offset)=624·64/2^(μ) of thecorresponding serving cell. In the above, the TAG means a group havingthe same time synchronization value, and the uplink time synchronizationof the serving cells belonging to the group is considered to be thesame.

FIG. 2H illustrates a diagram for describing the bandwidth partswitching operation in a serving cell in which an additional uplinkaccording to an embodiment of the disclosure is configured.

In FIG. 2G, the uplink/downlink BWP operation is summarized in a generalsituation, that is, one downlink and one uplink per serving cell.However, in the NR, as described above, it is possible to simultaneouslyconfigure one downlink and two uplinks for a serving cell by configuringa SUL as an additional uplink.

In addition, in the case of the SUL, a frame structure different fromthat of the existing uplink may be provided, and a downlink existing asa pair may exist in association with the SUL. If the SUL is set to theLTE frequency, the downlink frequency existing in the SUL and the pairmay also be the LTE frequency.

Also, it can be divided into 4 cases as follows depending on what typeof SUL is configured.

In one embodiment of CASE 1 (2 h-05), when the downlink 2 h-10 anduplink 2 h-15 of the serving cell are configured as the paired spectrumand the SUL 2 h-25 is also configured as another downlink 2 h-20 andpaired spectrum present in the pair.

In one embodiment of CASE 2 (2 h-30), when the downlink 2 h-35 anduplink 2 h-40 of the serving cell are configured as the paired spectrumand the SUL 2 h-50 is also configured as another downlink 2 h-45 andunpaired spectrum present in the pair.

In one embodiment of CASE 3 (2 h-55), when the downlink 2 h-60 anduplink 2 h-65 of the serving cell are configured in the unpairedspectrum and the SUL 2 h-75 is also configured as another downlink 2h-70 and unpaired spectrum present in the pair.

In one embodiment of CASE 4 (2 h-80), when the downlink 2 h-85 anduplink 2 h-90 of the serving cell are configured in the unpairedspectrum and the SUL 2 h-100 is also configured as another downlink 2h-95 and paired spectrum present in the pair.

The terminal can distinguish the BWP operation according four cases inwhich the SUL is configured. That is, it is defined in the Paired BWPand Unpaired BWP operations depending on what the corresponding NUL andSUL operates when the downlink BWP switching is received. The UnpairedBWP operation refers to an operation of switching to the BWP with whichthe uplink is also associated according to the downlink BWP switching,and the paired BWP operation refers to an operation of maintaining thecurrent uplink BWP regardless of the downlink BWP switching andperforming the BWP switching only when an independent uplink BWPswitching is indicated.

TABLE 5 Scenario for BWP operation when two uplinks exist SupplementaryNormal UL (NUL) UL (SUL) BWP operation CASE 1 Downlink of Anotherdownlink Paired BWP serving cell and and paired operation pairedspectrum spectrum (FDD) (FDD) CASE 2 Downlink of Another downlink PairedBWP serving cell and and unpaired operation paired spectrumspectrum(TDD) (FDD) CASE 3 Downlink of Another downlink NUL: Unpairedserving cell and and unpaired BWP operation unpaired spectrum spectrum(TDD) SUL: Paired BWP (TDD) operation CASE 4 Downlink of Anotherdownlink NUL: Unpaired serving cell and and paired BWP operationunpaired spectrum spectrum (FDD) SUL: Paired BWP (TDD) operation

The operation in which the terminal is instructed by the uplink/downlinkscheduling, that is, the BWP switching in the state in which the servingcell is configured as the SUL can be summarized in the following table.

TABLE 6 BWP switching operation when two uplinks exist Paired spectrum(CASE 1 & 2) Unpaired spectrum (CASE 3 & 4) Downlink Instruct switchingto Instruct switching to corresponding scheduling corresponding BWP,including BWP, including specific BWP index specific BWP index in DCI 1for in DCI 1 for downlink scheduling => downlink scheduling => Bothdownlink BWP and linked Switch to BWP indicated only NUL uplink BWP(NUL) are by downlink BWP and maintain switched to indicated BWP, andSUL uplink BWP (NUL, SUL) into maintains current uplink BWP currentconfiguration (NUL: Unpaired BWP operation) (Paired BWP operation) (SUL:Paired BWP operation) Uplink scheduling Instruct switching to Instructswitching to corresponding for NUL corresponding BWP, including BWP,including specific BWP index specific BWP index in DCI 0 for in DCI 0for uplink scheduling of uplink scheduling of NUL => NUL => Switch toBWP indicated only Both uplink MAT of NUL and by uplink BWP of NUL andlinked downlink BWP are switched maintain downlink BWP into to indicatedBWP, and SUL current configuration. Maintain maintains current uplinkBWP SUL BWP into current (NUL: Unpaired BWP operation) configuration(SUL: Paired BWP operation) (Paired BWP operation) Uplink schedulingInstruct switching to Instruct switching to corresponding for SULcorresponding BWP, including BWP, including specific BWP index specificBWP index in DCI 0 for in DCI 0 for uplink scheduling of uplinkscheduling of SUL => SUL => Switch to BWP indicated only Switch to BWPindicated only by by uplink BWP of SUL and uplink BWP of SUL andmaintain maintain downlink BWP and downlink BWP and BWP of NUL BWP ofNUL into current into current configuration configuration (DL: PairedBWP operation) (DL: Paired BWP operation) (NUL: Paired BWP operation)(NUL: Paired BWP operation)

In addition, if the terminal of the serving cell in which the SUL isconfigured is operating at the third BWP and then the BWP timer(BWP-inactivityTimer) expires, the operation to make the fallback to thesecond BWP can be summarized by being classified into the case in whichthe uplink/downlink is operating in the paired spectrum and the case inwhich the uplink/downlink is operating in the unpaired spectrum.

For the above two cases, the BWP switching operation of the terminalwhen the BWP timer of the terminal expires can be summarized as shown inthe table below.

TABLE 7 BWP timer expiration operation when two uplinks exist Pairedspectrum (CASE 1 & 2) Unpaired spectrum (CASE 3 & 4) Bwp-inactivity WhenDCI 1 for downlink When DCI 1 for downlink Timer scheduling is receivedand the scheduling or DCI 0 for uplink start corresponding DCI indicatesscheduling of NUL is received and (BWP timer second BWP other than thirdthe corresponding DCI indicates starts) BWP, Bwp-inactivityTimer startssecond BWP other than third BWP, Bwp-inactivityTimer starts UponDownlink: Switch to second BWP Downlink: Switch to second BWP of expiryof of downlink already configured downlink already configuredBwp-inactivity Uplink of NUL: Maintain Uplink of NUL: Switch to secondTimer operation in uplink BWP BWP of uplink already configured (BWPtimer currently activated Uplink of SUL: Maintain operation expires)Uplink of SUL: Maintain in uplink BWP currently activated operation inuplink BWP currently activated

In the case of CASE 3 and CASE 4 of the disclosure, the uplink secondBWP (UL default BWP) may be one of the BWPs configured in the NUL andmay have the same value as the BWP index in the downlink second BWP (DLdefault BWP). However, even if the uplink BWP of the SUL has the samevalue as the BWP index for the downlink second BWP (DL default BWP),this is not the default BWP. This is because the BWP of the SUL is notassociated with the downlink BWP of the serving cell.

In the case of CASE 3 and CASE 4, that is, when the serving cell inwhich the SUL is configured operates as the TDD cell, the N_(TA offset)value may be determined. In the above case, theN_(TA_offset)=624·64/2^(μ) in the TAG in which the corresponding servingcell exists.

In the case of CASE 1, that is, when the serving cell in which the SULis configured operates as the FDD cell, the N_(TA offset) value may bedetermined. In the above case, if any of the serving cells present inthe corresponding TAG operates in the unpaired spectrum,N_(TA_offset)=624·64/2^(μ) and if all the serving cells present in thecorresponding TAG operates in the paired spectrum, N_(TA offset) is 0.

For CASE 2, the SUL may consider operating as the TDD cell (if operatingin the LTE frequency, then the SUL may match the synchronizationassociated with other LTE uplink transmissions) in order to match theuplink synchronization. That is, the N_(TA offset) value is not zero,and the N_(TA offset) value in the NR may be equal to the N_(TA offset)in the LTE.

Here, the problem is that the terminal cannot know whether the SUL isthe paired spectrum (CASE 1) or the unpaired spectrum (CASE 2).Therefore, to solve this problem, the system information indicateswhether the N_(TA offset) corresponding to the SUL is 0,N_(TA_offset)=624·64/2^(μ), or N_(TA offset) values of the LTE. In thesame sense as in the above method, the system information indicates inwhich of the FDD, NR TDD, or LTE TDD the SUL operates. Alternatively,the terminal sets the TAG to the longest N_(TA offset) value among theN_(TA offset) requesting the N_(TA offset).

FIG. 2I illustrates a diagram illustrating a BWP switching operation ina case where two uplinks exist in an operation of a terminal accordingto an embodiment of the disclosure. This drawing is a diagram showingthe summarization of the contents of Table 4 and Table 5 as described inFIG. 2H above, and the relevant description refers to the abovecontents.

In step 2 i-05, the terminal receives the uplink/downlink BWPconfiguration from the base station and performs an uplink/downlinkoperation in a specific BWP. The above uplink BWP and downlink BWP canoperate as paired or unpaired and are activated independently.

In step 2 i-10, the terminal may receive the DCI on the PDCCH of thebase station to receive the downlink scheduling, and the BWP index mayexist to instruct the downlink BWP to be switched in the control signal.The corresponding BWP index may indicate one of the BWPs preset by thebase station as an RRC control message.

In step 2 i-15, the terminal performs different operations depending onwhether the uplink and the downlink are currently operating in thepaired spectrum. If the uplink and the downlink operate in the pairedspectrum, the uplink and downlink correspond to CASE 1 and CASE 2 ofTable 4 and Table 5. In step 2 i-20, the terminal switches to the BWPindicated by only the downlink BWP and the uplink BWP (NUL and SUL)maintains the current configuration.

However, if the uplink and the downlink do not operate in the pairedspectrum, that is, if the uplink and downlink correspond to CASE 3 andCASE 4 in Table 4 and Table 5, in step 2 i-25, the terminal switchesboth of the downlink BWP and the linked NUL uplink BWP (NUL) to theindicated BWPs, and the SUL maintains the current uplink BWP.

Next, in step 2 i-30, the terminal may receive the DCI on the PDCCH ofthe base station to receive the uplink scheduling, and the BWP index mayexist to instruct the uplink BWP to be switched in the control signal.The indicator may be an indicator corresponding to the NUL or the SUL (2i-35). In the case of the NUL, it is checked in step 2 i-40 that theuplink and downlink operate in the paired spectrum. If the uplink anddownlink operates in the paired spectrum, in step 2 i-45, only theuplink BWP of the NUL is switched to the indicated BWP, the downlink BWPmaintains the current configuration, and the BWP of the SUL alsomaintains the current configuration. If the uplink and downlink operatein the unpaired spectrum, both the uplink BWP of the NUL and the linkeddownlink BWP are switched to the indicated BWP, and the SUL maintainsthe current uplink BWP.

In step 2 i-35, if the terminal receives the uplink scheduling of theSUL, in step 2 i-55, the terminal switches to the indicated BWP only inthe uplink BWP of the SUL, and the downlink BWP and the BWP of the NULmaintain the current configuration.

FIG. 2J illustrates a BWP timer expiration operation in a case where twouplinks exist in an operation of a terminal according to an embodimentof the disclosure. This drawing is a diagram showing the summarizationof the contents of Table 6 as described in FIG. 2H above, and therelevant description refers to the above contents.

The terminal receives the uplink/downlink BWP configuration from thebase station and performs an uplink/downlink operation in a specificBWP. The above uplink BWP and downlink BWP can operate as paired orunpaired and are activated independently.

In step 2 j-05, the terminal may receive the DCI on the PDCCH of thebase station to receive the downlink or uplink scheduling, and the BWPindex may exist to instruct the downlink BWP to be switched in thecontrol signal. The corresponding BWP index may indicate one of the BWPspreset by the base station as an RRC control message.

Upon receiving the message, the terminal operates the BWP timer in step2 j-10. The terminal may receive the setting of the expiration time ofthe BWP timer in advance from the base station in the previous step.

In step 2 j-15, if the BWP timer of the terminal expires, the terminalconfirms whether the uplink and the downlink operate in the pairedspectrum (2 j-20), and in the case of the paired spectrum (CASE 1 & 2),in step 2 j-25, the downlink BWP is switched to the second BWP of thedownlink already configured, the uplink of the NUL maintains theoperation in the currently activated uplink BWP, and the uplink of theSUL maintains the operation in the currently activated uplink BWP.

If the uplink and downlink are the unpaired spectrum (CASE 3 & 4), thedownlink BWP switches to the second BWP of the downlink alreadyconfigured, the uplink of the NUL switches to the second BWP of theuplink already configured, and the uplink of the SUL maintains theoperation in the currently activated uplink BWP (2 j-30).

In step 2 j-15, if the BWP timer of the terminal does not expire, theterminal maintains the operations of the uplink and downlink BWPcurrently activated.

FIG. 2K illustrates an operation of the terminal according to anembodiment of the disclosure, in particular, a method for setting, by aterminal, uplink time synchronization in a serving cell where anadditional uplink is configured.

FIG. 2K(a) shows an operation of the terminal in a general situation inwhich one uplink is configured, and in particular, describes a methodfor determining a N_(TA offset) value for setting uplink timesynchronization. In step 2 k-05, the terminal checks whether the uplinkand downlink of the serving cell are operating in the paired spectrum.If the terminal operates in the paired spectrum, the terminal sets theN_(TA offset) value to 0 in step 2 k-10. However, if the terminaloperates in the unpaired spectrum, the terminal sets to beN_(TA_offset)=624·64/2^(μ) in step 2 k-15. In the above, μ is determinedaccording to what numerology is used in the corresponding BWP, and thedetailed values thereof are summarized in Table 3.

FIG. 2K(b) shows an operation of the terminal in the case in which twouplinks are configured, that is, in the case where the SUL isadditionally configured in the basic uplink and downlink, and inparticular, describes a method for determining a N_(TA offset) value forsetting an uplink time synchronization. For CASE 2 in the BWP scenario,the SUL may consider operating as the TDD cell (if operating in the LTEfrequency, then the SUL may match the synchronization associated withother LTE uplink transmissions) in order to match the uplinksynchronization. That is, the N_(TA offset) value is not zero, and theN_(TA offset) value in the NR may be equal to the N_(TA offset) value inthe LTE.

Here, the problem is that the terminal cannot know whether the SUL isthe paired spectrum (CASE 1) or the unpaired spectrum (CASE 2).Therefore, to solve this problem, the system information indicateswhether the N_(TA offset) corresponding to the SUL is 0,N_(TA_offset)=624·64/2^(μ), or N_(TA offset) values of the LTE.

In the same sense as in the above method, the system informationindicates in which of the FDD, NR TDD, or LTE TDD the SUL operates.Alternatively, the terminal sets the TAG to the longest N_(TA offset)value among the N_(TA offset) requesting the N_(TA offset). That is, instep 2 k-20, the terminal applies frame structure type information ofthe SUL previously configured from the base station as the systeminformation. The above information may be known again via the RRCmessage.

In step 2 k-25, if the terminal has received the N_(TA offset) value ofthe LTE from the base station, the terminal sets the N_(TA offset) tothe N_(TA offset) value of the LTE (2 k-30). If the terminal does notreceive the N_(TA offset) value of the LTE from the base station insteps 2 k-25, the terminal sets the N_(TA offset) value to 0 in the caseof the paired spectrum in step 2 k-40 according to whether theuplink/downlink operates in the paired spectrum (2 k-35). However, ifthe terminal operates in the unpaired spectrum, the terminal sets to beN_(TA offset)=624·64/2^(μ) in step 2 k-45. In the above, μ is determinedaccording to what numerology is used in the corresponding BWP, and thedetailed values thereof are summarized in Table 3.

FIG. 2L illustrates a configuration of the terminal according to anembodiment of the disclosure.

Referring to FIG. 2L, the terminal includes a radio frequency (RF)processor 2 l-10, a baseband processor 2 l-20, a memory 2 l-30, and acontroller 2 l-40.

The RF processor 2 l-10 serves to transmit/receive a signal through aradio channel, such as band conversion and amplification of a signal.That is, the RF processor 2 l-10 up-converts a baseband signal providedfrom the baseband processor 2 l-20 into an RF band signal and thentransmits the RF band signal through an antenna and down-converts the RFband signal received through the antenna into the baseband signal. Forexample, the RF processor 2 l-10 may include a transmitting filter, areceiving filter, an amplifier, a mixer, an oscillator, a digital toanalog converter (DAC), an analog to digital converter (ADC), or thelike.

In the above figure, only one antenna is illustrated, but the terminalmay include a plurality of antennas. Further, the RF processor 2 l-10may include the plurality of RF chains. Further, the RF processor 2 l-10may perform beamforming. For the beamforming, the RF processor 2 l-10may adjust a phase and a size of each of the signals transmitted andreceived through a plurality of antennas or antenna elements. Inaddition, the RF processor may perform MIMO and may receive a pluralityof layers when performing a MIMO operation.

The baseband processor 2 l-20 performs a conversion function between thebaseband signal and the bit string according to a physical layerstandard of the system. For example, when data are transmitted, thebaseband processor 2 l-20 generates complex symbols by coding andmodulating a transmitted bit string. Further, when data are received,the baseband processor 2 l-20 recovers the received bit string bydemodulating and decoding the baseband signal provided from the RFprocessor 2 l-10. For example, according to the orthogonal frequencydivision multiplexing (OFDM) scheme, when data are transmitted, thebaseband processor 2 l-20 generates the complex symbols by coding andmodulating the transmitting bit string, maps the complex symbols tosub-carriers, and then performs an inverse fast Fourier transform (IFFT)operation and a cyclic prefix (CP) insertion to configure the OFDMsymbols.

Further, when data are received, the baseband processor 2 l-20 dividesthe baseband signal provided from the RF processor 2 l-10 in an OFDMsymbol unit and recovers the signals mapped to the sub-carriers by afast Fourier transform (FFT) operation and then recovers the receivedbit string by the demodulation and decoding.

The baseband processor 2 l-20 and the RF processor 2 l-10 transmit andreceive a signal as described above. Therefore, the baseband processor 2l-20 and the RF processor 2 l-10 may be called a transmitter, areceiver, a transceiver, or a communication interface. Further, at leastone of the baseband processor 2 l-20 and the RF processor 2 l-10 mayinclude a plurality of communication modules to support a plurality ofdifferent radio access technologies.

Further, at least one of the baseband processor 2 l-20 and the RFprocessor 2 l-10 may include different communication modules to processsignals in different frequency bands. For example, the different radioaccess technologies may include the WLAN (for example: IEEE 802.11), acellular network (for example: LTE), or the like. Further, the differentfrequency bands may include a super high frequency (SHF) (for example:2.5 GHz, 5 GHz) band, a millimeter wave (for example: 60 GHz) band.

The memory 2 l-30 stores data such as basic programs, applicationprograms, and configuration information or the like for the operation ofthe terminal. In particular, the memory 2 l-30 may store informationassociated with a second access node performing wireless communicationusing a second radio access technology. Further, the memory 2 l-30provides the stored data according to the request of the controller 2l-40.

The controller 2 l-40 controls the overall operations of the terminal.For example, the controller 2 l-40 transmits/receives a signal throughthe baseband processor 2 l-20 and the RF processor 2 l-10. Further, thecontroller 2 l-40 records and reads data in and from the memory 2 l-30.For this purpose, the controller 2 l-40 may include at least oneprocessor. For example, the controller 2 l-40 may include acommunication processor (CP) performing a control for communication andan application processor (AP) controlling an upper layer such as theapplication programs.

FIG. 2M illustrates a configuration of a base station according to anembodiment of the disclosure.

As illustrated in FIG. 2M, the base station is configured to include anRF processor 2 m-10, a baseband processor 2 m-20, a backhaulcommunication interface 2 m-30, a memory 2 m-40, and a controller 2m-50.

The RF processor 2 m-10 serves to transmit/receive a signal through aradio channel, such as band conversion and amplification of a signal.That is, the RF processor 2 m-10 up-converts a baseband signal providedfrom the baseband processor 2 m-20 into an RF band signal and thentransmits the RF band signal through an antenna and down-converts the RFband signal received through the antenna into the baseband signal. Forexample, the RF processor 2 m-10 may include a transmitting filter, areceiving filter, an amplifier, a mixer, an oscillator, a DAC, an ADC,etc.

In the above figure, only one antenna is illustrated, but the firstaccess node may include a plurality of antennas. Further, the RFprocessor 2 m-10 may include the plurality of RF chains. Further, the RFprocessor 2 m-10 may perform the beamforming. For the beamforming, theRF processor 2 m-10 may adjust a phase and a size of each of the signalstransmitted and received through a plurality of antennas or antennaelements. The RF processor may perform a downward MIMO operation bytransmitting one or more layers.

The baseband processor 2 m-20 performs a conversion function between thebaseband signal and the bit string according to the physical layerstandard of the first radio access technology. For example, when dataare transmitted, the baseband processor 2 m-20 generates complex symbolsby coding and modulating a transmitted bit string. Further, when dataare received, the baseband processor 2 m-20 recovers the received bitstring by demodulating and decoding the baseband signal provided fromthe RF processor 2 m-10. For example, according to the OFDM scheme, whendata are transmitted, the baseband processor 2 m-20 generates thecomplex symbols by coding and modulating the transmitting bit string,maps the complex symbols to the sub-carriers, and then performs the IFFToperation and the CP insertion to configure the OFDM symbols.

Further, when data are received, the baseband processor 2 m-20 dividesthe baseband signal provided from the RF processor 2 m-10 in an OFDMsymbol unit and recovers the signals mapped to the sub-carriers by anFFT operation and then recovers the receiving bit string by thedemodulation and decoding. The baseband processor 2 m-20 and the RFprocessor 2 m-10 transmit and receive a signal as described above.Therefore, the baseband processor 2 m-20 and the RF processor 2 m-10 maybe called a transmitter, a receiver, a transceiver, a communicationinterface, or a wireless communication interface.

The backhaul communication interface 2 m-30 provides an interface forperforming communication with other nodes within the network. That is,the backhaul communication interface 2 m-30 converts bit stringstransmitted from the main base station to other nodes, for example, anauxiliary base station, a core network, etc., into physical signals andconverts the physical signals received from other nodes into the bitstrings.

The memory 2 m-40 stores data such as basic programs, applicationprograms, and configuration information for the operation of the mainbase station. In particular, the memory 2 m-40 may store the informationon the bearer allocated to the accessed terminal, the measured resultsreported from the accessed terminal, etc. Further, the memory 2 m-40 maystore information that is a determination criterion on whether toprovide a multiple connection to the terminal or stop the multipleconnection to the terminal. Further, the memory 2 m-40 provides thestored data according to the request of the controller 2 m-50.

The controller 2 m-50 controls the overall operations of the main basestation. For example, the controller 2 m-50 transmits/receives a signalthrough the baseband processor 2 m-20 and the RF processor 2 m-10 or thebackhaul communication interface 2 m-30. Further, the controller 2 m-50records and reads data in and from the memory 2 m-40. For this purpose,the controller 2 m-50 may include at least one processor.

The methods according to the embodiments described in claims orspecification of the disclosure may be implemented in hardware,software, or a combination of hardware and software.

When the methods are implemented in the software, a computer readablestorage medium storing at least one program (software module) may beprovided. At least one programs stored in the computer readable storagemedium is configured for execution by at least one processor within anelectronic device. At least one program includes instructions that allowthe electronic device to execute the methods according to theembodiments described in the claims or specification of the disclosure.

The program (software module, software) may be stored in a random accessmemory, a non-volatile memory including a flash memory, a read onlymemory (ROM), an electrically erasable programmable read only memory(EEPROM), a magnetic disc storage device, a compact disc-ROM (CD-ROM),digital versatile discs (DVDs) or other types of optical storagedevices, and a magnetic cassette. Alternatively, the programs may bestored in the memory that is configured of combinations of some or allof the memories. Further, each configuration memory may also be includedin plural.

Further, the program may be stored in an attachable storage device thatmay be accessed through communication networks such as Internet, anintranet, a local area network (LAN), a wide LAN (WLAN), and a storagearea network (SAN) or a communication network configured in acombination thereof. The storage device may access a device performingthe embodiment of the disclosure through an external port. Further, aseparate storage device on the communication network may also access adevice performing the embodiment of the disclosure.

In the detailed embodiments of the disclosure, components included inthe disclosure are represented by a singular number or a plural numberaccording to the detailed embodiment as described above. However, theexpressions of the singular number or the plural number are selected tomeet the situations proposed for convenience of explanation and thepresent disclosure is not limited to the single component or the pluralcomponents and even though the components are represented in plural, thecomponent may be configured in a singular number or even though thecomponents are represented in a singular number, the component may beconfigured in plural.

Although the exemplary embodiments of the disclosure have been disclosedfor illustrative purposes, various modifications, additions andsubstitutions are possible, without departing from the scope and spiritof the disclosure as disclosed in the accompanying claims. Accordingly,the scope of the disclosure is not construed as being limited to thedescribed embodiments but is defined by the appended claims as well asequivalents thereto.

Although the present disclosure has been described with variousembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

What is claimed is:
 1. A method performed by a terminal in a wirelesscommunication system, the method comprising: receiving, from a basestation, system information including configuration information on asupplementary uplink (SUL) of a cell associated with the base station,and information on an offset applied to a timing advance, wherein anuplink of the cell and the SUL are configured for one downlink of thecell; determining a transmission timing for an uplink signal to betransmitted on the SUL, based on the information on the offset appliedto the timing advance; and transmitting, to the base station, the uplinksignal on the SUL, based on the determined transmission timing.
 2. Themethod of claim 1, wherein the transmission timing for the uplink signalis determined based on the timing advance between the one downlink andthe SUL, and the offset applied to the timing advance.
 3. The method ofclaim 1, wherein a value of the offset includes 0, in case that a duplexmode of the cell in which a transmission of the uplink signal takesplace is a frequency division duplex (FDD) mode.
 4. The method of claim1, wherein a value of the offset includes 39936, in case that a duplexmode of the cell in which a transmission of the uplink signal takesplace is a time division duplex (TDD) mode.
 5. The method of claim 1,wherein a value of the offset applied to the timing advance isdetermined based on a duplex mode of a cell in which a transmission ofthe uplink signal takes place and a frequency range of the cell.
 6. Amethod performed by a base station in a wireless communication system,the method comprising: transmitting, to a terminal, system informationincluding configuration information on a supplementary uplink (SUL) of acell associated with the base station, and information on an offsetapplied to a timing advance, wherein an uplink of the cell and the SULare configured for one downlink of the cell; and receiving, from theterminal, an uplink signal on the SUL based on a transmission timing,wherein the information on the offset applied to the timing advance isused for determining the transmission timing for the uplink signal. 7.The method of claim 6, wherein the transmission timing for the uplinksignal is determined based on the timing advance between the onedownlink and the SUL, and the offset applied to the timing advance. 8.The method of claim 6, wherein a value of the offset includes 0, in casethat a duplex mode of the cell in which a transmission of the uplinksignal takes place is a frequency division duplex (FDD) mode.
 9. Themethod of claim 6, wherein a value of the offset includes 39936, in casethat a duplex mode of a cell in which a transmission of the uplinksignal takes place is a time division duplex (TDD) mode.
 10. The methodof claim 6, wherein a value of the offset applied to the timing advanceis determined based on a duplex mode of a cell in which a transmissionof the uplink signal takes place and a frequency range of the cell. 11.A terminal in a wireless communication system, the terminal comprising:a transceiver; and a controller configured to: receive, via thetransceiver from a base station, system information includingconfiguration information on a supplementary uplink (SUL) of a cellassociated with the base station, and information on an offset appliedto a timing advance, wherein an uplink of the cell and the SUL areconfigured for one downlink of the cell; determine a transmission timingfor an uplink signal to be transmitted on the SUL, based on theinformation on the offset applied to the timing advance; and transmit,via the transceiver to the base station, the uplink signal on the SUL,based on the determined transmission timing.
 12. The terminal of claim11, wherein the transmission timing for the uplink signal is determinedbased on the timing advance between the one downlink and the SUL, andthe offset applied to the timing advance.
 13. The terminal of claim 11,wherein a value of the offset includes 0, in case that a duplex mode ofa cell in which a transmission of the uplink signal takes place is afrequency division duplex (FDD) mode.
 14. The terminal of claim 11,wherein a value of the offset includes 39936, in case that a duplex modeof a cell in which a transmission of the uplink signal takes place is atime division duplex (TDD) mode.
 15. The terminal of claim 11, wherein avalue of the offset applied to the timing advance is determined based ona duplex mode of a cell in which a transmission of the uplink signaltakes place and a frequency range of the cell.
 16. A base station in awireless communication system, the base station comprising: atransceiver; and a controller configured to: transmit, via thetransceiver to a terminal, system information including configurationinformation on a supplementary uplink on (SUL) of a cell associated withthe base station, and information on an offset applied to a timingadvance, wherein an uplink of the cell and the SUL are configured forone downlink of the cell, and receive, via the transceiver from theterminal, an uplink signal on the SUL based on a transmission timing,and wherein the information on the offset applied to the timing advanceis used for determining the transmission timing for the uplink signal.17. The base station of claim 16, wherein the transmission timing forthe uplink signal is determined based on the timing advance between theone downlink and the SUL, and the offset applied to the timing advance.18. The base station of claim 16, wherein a value of the offset includes0, in case that a duplex mode of a cell in which a transmission of theuplink signal takes place is a frequency division duplex (FDD) mode. 19.The base station of claim 16, wherein a value of the offset includes39936, in case that a duplex mode of a cell in which a transmission ofthe uplink signal takes place is a time division duplex (TDD) mode. 20.The base station of claim 16, wherein a value of the offset applied tothe timing advance is determined based on a duplex mode of a cell inwhich a transmission of the uplink signal takes place and a frequencyrange of the cell.